"I got breast implants 14 years ago and I'm still happy with their appearance, but a friend just had her 10-year-old implants redone because her doctor said she had to. Is that true?" False.

Dr. Eisenberg explains, "Breast implants don't have an expiration date. They only need to be replaced if they deflate (saline) or rupture (silicone), and they're not fragile."

It's no surprise that women believe that implants have a shelf life, but what causes the confusion? Breast implants come with a free lifetime product replacement policy. Manufacturers also offer a 10-year warranty to defray some costs of implant replacement surgery. "When women hear this, some assume they have to replace their implants after 10 years," Dr. Eisenberg says.

Don't be misled by the warranty. "Like breast implants, your refrigerator comes with a warranty, but you don't automatically replace it when that warranty expires," Dr. Eisenberg says. "You'll probably keep it until it breaks down, unless you are redoing your kitchen and want a bigger or smaller model."

Women sometimes opt to replace their implants for bigger or smaller ones after childbirth, weight gain or a change of heart. "I recently removed saline implants from a woman who wanted to go bigger after 19 years, and her implants looked the same as the day I put them in," Dr. Eisenberg reports.

About 1-3 percent of the 300,000-plus women in the United States who have a breast augmentation each year eventually have surgery to replace implants that have ruptured or deflated.

"The most common reason that an implant breaks is because it develops a fold in one spot. Over time, that fold might move back and forth, weaken, and then break, in the same way that a paper clip might break after it has been bent multiple times. Dr. Eisenberg has found that if an implant doesn't deflate from fold failure in the first 6-7 years, the likelihood of this happening seems to decrease, not increase, over time.

Implant replacement costs money, requires time off from work, and exposes women to the risks of surgery and anesthesia. As far as replacing implants every 10 years, Dr. Eisenberg invokes the old maxim: "If it ain't broke, don't fix it."